1. Field of the Invention
The present invention relates to a printing apparatus capable of printing print data received from an external apparatus.
2. Description of the Related Art
In recent years, there has been known a system that reserves print data transmitted from an external apparatus such as a personal computer (PC) in a printing apparatus and prints the print data in response to a user's predetermined operation on an operation panel of the printing apparatus. The printing in this manner is called reservation printing.
An example of a conventional technique regarding reservation printing can be found in Japanese Patent Application Publication No. 2000-76028. Japanese Patent Application Publication No. 2000-76028 suggests a method where a PC adds a password to a print job and transmits the print job to a printing apparatus. The printing apparatus prints transmitted data of the print job in response to a password input on the operation panel of the printing apparatus, when it is the same as the added password. This method for reservation printing may be also called secure printing, confidential printing, private printing, and authentication printing.
In general, a user is required to input a password to perform print operation of a reserved print job, but user operation to cancel a print job (hereinafter referred to as “cancel operation”) is not restricted.
There are mainly three reasons why cancel operation is not generally restricted. The first reason is that security of a print product can be maintained even without restricting cancel operation of a secure print job because there is no chance for others to see the print product. The second reason is that there is an upper limit to the number of secure print jobs that can be reserved in the printing apparatus. More specifically, there is a possibility that secure print jobs reserved in the printing apparatus may be left as it is for a long time. When the number of the reserved secure print jobs reaches the reservable upper limit, the printing apparatus cannot receive secure print jobs any more. If cancel operation of secure print jobs are restricted in such a situation, only a user knowing the passwords of the secure print jobs left in the printing apparatus could cancel the print jobs. The third reason is to improve operability. When a secure print job has been transmitted mistakenly or a secure print job becomes unnecessary due to change of a situation after transmission of the secure print job, a user cancels the secure print job on an operation unit of the printing apparatus. At that time, if the user is required to input a password, the operation would become complicated.